1. Field of the Invention
The present invention relates to a camera comprising a lens optical system having a movable lens group.
2. Related Background Art
Conventionally known as a camera comprising a lens optical system having a movable lens group is one equipped with a lens barrel having four lens groups, all of which are attached to a frame expandable from the camera body, where as the lens groups are appropriately moved in the optical axis direction by use of a cam mechanism so as to change the power and adjust the focus, as disclosed in Japanese Patent Application Laid-Open No. HEI 7-20369.
This lens barrel comprises a barrier blade, disposed in front of a taking optical system, for opening/closing an optical path; a lens driving mechanism for advancing/retracting a part of the taking optical system upon a focusing operation of the taking optical system; a barrier driving mechanism for opening/closing the barrier blade; a first transmission mechanism for transmitting a driving force of a driving source to the lens driving mechanism; and a second transmission mechanism for transmitting the driving force of the driving source to the barrier driving mechanism, in which the transmission of the driving force to the second transmission mechanism is switched via a clutch mechanism as appropriate. The switching of the clutch mechanism is carried out by utilizing a pivotal member, so as to enhance the space efficiency, thereby reducing the size of the camera.
The camera equipped with this lens barrel comprises a barrier driving ring, as a barrier driving mechanism, rotatable when driven by a focus motor; and opens/closes the barrier blade by rotating the barrier driving ring. In the barrier driving mechanism, a stopper for restricting the rotary movement area of the barrier driving ring may be disposed so as to rotationally move the barrier driving ring until the latter abuts against the stopper, thereby opening/closing the barrier blade. When the barrier blade is thus opened/closed, it becomes easier to drive and control the focus motor upon opening/closing the barrier blade.
If the barrier driving ring is left for a long time in the state in contact with the stopper, however, the barrier driving ring may break upon creeping due to the internal stress occurring within the barrier driving ring.
In order to overcome such a problem, it is an object of the present invention to provide a camera which can prevent a moving member from breaking due to creeping.
In order to achieve such an object, the present invention provides a camera comprising a moving member movable in response to a driving force of a driving source; movement control means for controlling movement of the moving member by regulating driving of the driving source; and a stopper for restricting a moving area of the moving member; wherein, when moving the moving member to a position of the stopper, the movement control means moves the moving member until the moving member abuts against the stopper and moves the moving member in reverse away from the stopper.
In the camera in accordance with the present invention, the moving member may be a member constituting a barrier opening/closing mechanism for opening/closing a taking optical system.
In the camera in accordance with the present invention, the moving member may be a lens barrel.
According to these aspects of the present invention, when moving the moving member to the position of the stopper, the moving member is moved until it abuts against the stopper and then is moved in reverse so as to be separated from the stopper, whereby the moving member can be prevented from breaking upon creeping when the moving member is pressed by the stopper for a long time.
The present invention will be more fully understood from the detailed description given hereinbelow and the accompanying drawings, which are given by way of illustration only and are not to be considered as limiting the present invention.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art from this detailed description.